Search

Understanding and characterizing very low-energy ($\sim$eV) background sources is a must in rare-event searches. Oscura, an experiment aiming to probe electron recoils from sub-GeV dark matter using a 10-kg skipper-CCD detector, has recently fabricated its first two batches of sensors. In this work, we present the characterization of defects/contaminants identified in the buried-channel region of these newly fabricated skipper-CCDs. These defects/contaminants produce deferred charge from trap emission in the images next to particle tracks, which can be spatially resolved due to the sub-electron resolution achieved with these sensors. Using the trap-pumping technique, we measured the energy and cross section associated to these traps in three Oscura prototype sensors from different fabrication batches which underwent different gettering methods during fabrication. Results suggest that the type of defects/contaminants is more closely linked to the fabrication batch rather than to the gettering method used. The exposure-dependent single-electron rate (SER) of one of these sensors was measured $\sim$100~m underground, yielding $(1.8\pm 0.3)\times10^{-3}~e^-$/pix/day at 131K. The impact of the identified traps on the measured exposure-dependent SER is evaluated via a Monte Carlo simulation. Results suggest that the exposure-dependent SER of Oscura prototype sensors would be lower in lower background environments as expected.

$\eta$ Tel is an 18 Myr system with a 2.09 M$_{\odot}$ A-type star and an M7-M8 brown dwarf companion, $\eta$ Tel B, separated by 4.2'' (208 au). High-contrast imaging campaigns over 20 years have enabled orbital and photometric characterization. $\eta$ Tel B, bright and on a wide orbit, is ideal for detailed examination. We analyzed three new SPHERE/IRDIS coronagraphic observations to explore $\eta$ Tel B's orbital parameters, contrast, and surroundings, aiming to detect a circumplanetary disk or close companion. Reduced IRDIS data achieved a contrast of 1.0$\times 10^{-5}$, enabling astrometric measurements with uncertainties of 4 mas in separation and 0.2 degrees in position angle, the smallest so far. With a contrast of 6.8 magnitudes in the H band, $\eta$ Tel B's separation and position angle were measured as 4.218'' and 167.3 degrees, respectively. Orbital analysis using Orvara code, considering Gaia-Hipparcos acceleration, revealed a low eccentric orbit (e $\sim$ 0.34), inclination of 81.9 degrees, and semi-major axis of 218 au. $\eta$ Tel B's mass was determined to be 48 \MJup, consistent with previous calculations. No significant residual indicating a satellite or disk around $\eta$ Tel B was detected. Detection limits ruled out massive objects around $\eta$ Tel B with masses down to 1.6 \MJup at a separation of 33 au., Comment: 13 pages, 10 figures, accepted for publication in A&A (01/05/2024)

We present ALMA 12-m, 7-m & Total Power (TP) Array observations of the FU Orionis outbursting system, covering spatial scales ranging from 160 to 25,000 au. The high-resolution interferometric data reveals an elongated $^{12}$CO(2-1) feature previously observed at lower resolution in $^{12}$CO(3-2). Kinematic modeling indicates that this feature can be interpreted as an accretion streamer feeding the binary system. The mass infall rate provided by the streamer is significantly lower than the typical stellar accretion rates (even in quiescent states), suggesting that this streamer alone is not massive enough to sustain the enhanced accretion rates characteristic of the outbursting class prototype. The observed streamer may not be directly linked to the current outburst but rather a remnant of a previous, more massive streamer that may have contributed enough to the disk mass to render it unstable and trigger FU Ori's outburst. The new data detects, for the first time, a vast, slow-moving carbon monoxide molecular outflow emerging from this object. To accurately assess the outflow properties (mass, momentum, kinetic energy), we employed $^{13}$CO(2-1) data to correct for optical depth effects. The analysis indicates that the outflow corresponds to swept-up material not associated with the current outburst, similar to slow-molecular outflows observed around other FUor and Class I protostellar objects.

The observed diversity of exoplanets can possibly be traced back to the planet formation processes. Planet-disk interactions induce sub-structures in the circumstellar disk that can be revealed via scattered light observations. However, a high-contrast imaging technique such as polarimetric differential imaging (PDI) must first be applied to suppress the stellar diffraction halo. In this work we present the PDI PiPelIne for NACO data (PIPPIN), which reduces the archival polarimetric observations made with the NACO instrument at the Very Large Telescope. Prior to this work, such a comprehensive pipeline to reduce polarimetric NACO data did not exist. We identify a total of 243 datasets of 57 potentially young stellar objects observed before NACO's decommissioning. The PIPPIN pipeline applies various levels of instrumental polarisation correction and is capable of reducing multiple observing setups, including half-wave plate or de-rotator usage and wire-grid observations. A novel template-matching method is applied to assess the detection significance of polarised signals in the reduced data. In 22 of the 57 observed targets, we detect polarised light resulting from a scattering of circumstellar dust. The detections exhibit a collection of known sub-structures, including rings, gaps, spirals, shadows, and in- or outflows of material. Since NACO was equipped with a near-infrared wavefront sensor, it made unique polarimetric observations of a number of embedded protostars. This is the first time detections of the Class I objects Elia 2-21 and YLW 16A have been published. Alongside the outlined PIPPIN pipeline, we publish an archive of the reduced data products, thereby improving the accessibility of these data for future studies., Comment: Accepted for publication in A&A. For more information on PIPPIN, see: https://pippin-naco.readthedocs.io/en/latest . The reduced images are available on Zenodo: https://zenodo.org/doi/10.5281/zenodo.8348803

Eruptive stars are a class of young stellar objects that show an abrupt increase in their luminosity. These burst-like episodes are thought to dominate the stellar accretion process during the class 0/class I stage. We present an overview of a survey of seven episodically accreting protostars aimed at studying their potentially complex circumstellar surroundings. The observations were performed with the instrument SPHERE, mounted at the VLT. We observed the eruptive stars in $H$-band with the near-infrared imager IRDIS and used the polarimeter to extract the polarized light scattered from the stars' surroundings. We produced polarized light images for three FUor objects, Z CMa, V960 Mon, and FU Ori, and four EXor objects, XZ Tau, UZ Tau, NY Ori, and EX Lup. We calculated the intrinsic polarization fraction for all the observed stars. In all systems we registered scattered light from around the primary star. FU Ori and V960 Mon are surrounded by complex structures including spiral-like features. In Z CMa, we detected a point source 0.7 arcsec to the northeast of the primary. Based on the astrometric measurements from archival Keck/NIRC2 data, we find this source to be a third member of the system. Further, Z CMa displays an outflow extending thousands of au. Unlike the other EXor objects in our sample, XZ Tau shows bright, extended scattered light structures, also associated with an outflow on a scale of hundreds of au. The other EXors show relatively faint disk-like structures in the immediate vicinity of the coronagraph. Asymmetric arms were only found around FUor objects, while faint disks seem to predominantly occur around EXors. Importantly, for Z CMa the detection of the faint extended structure questions previous interpretations of the system's dynamic state. The streamer which was associated with a fly-by object turned out to be part of a huge outflow extending 6000 au., Comment: Accepted for publication in A&A. 14 pages, 7 figures, 2 tables

The sample of planet-forming disks observed by high-contrast imaging campaigns over the last decade is mature enough to enable the demographical analysis of individual star-forming regions. We present the full census of Taurus sources with VLT/SPHERE polarimetric images available. The whole sample sums up to 43 targets (of which 31 have not been previously published) corresponding to one-fifth of the Class II population in Taurus and about half of such objects that are observable. A large fraction of the sample is apparently made up of isolated faint disks (equally divided between small and large self-shadowed disks). Ambient signal is visible in about one-third of the sample. This probes the interaction with the environment and with companions or the outflow activity of the system. The central portion of the Taurus region almost exclusively hosts faint disks, while the periphery also hosts bright disks interacting with their surroundings. The few bright disks are found around apparently older stars. The overall picture is that the Taurus region is in an early evolutionary stage of planet formation. Yet, some objects are discussed individually, as in an intermediate or exceptional stage of the disk evolution. This census provides a first benchmark for the comparison of the disk populations in different star forming regions., Comment: Accepted by A&A

We study the emission of gravitational waves from spheroidal magnetized strange stars for both an isolated slowly rotating star and a binary system. In the first case, we compute the quadrupole moment and the amplitude of gravitational waves that may be emitted. For the binary system, the tidal deformability is obtained by solving simultaneously the system of spheroidal structure equations and the Love number equation. These results are compared with the data inferred from the GW170817 event which is also used to calculate the mass and tidal deformability of the companion star in the binary system. Our model supports binary systems formed by magnetized strange stars describing reasonable signals of gravitational waves contrasted with other models of binary systems composed of magnetized hadronic stars and non-magnetized quark stars.

Charge Coupled Devices (CCD) are used for reactor neutrino experiments and already shown their potential in constraining new physics models. The prospect of a Skipper-CCD experiment looking for standard and beyond standard model physics (BSM) in a nuclear reactor has been recently evaluated for different benchmark scenarios. Here we report the installation of the first 2 g Skipper-CCD inside the containment building of a 2 GW$_{th}$ nuclear power plant, positioned 12 meters from the center of the reactor core. We discuss the challenges involved in the commissioning of the detector and present data acquired during reactor ON and reactor OFF periods, with the detector operating with a sub-electron readout noise of 0.17 e-. The ongoing efforts to improve sensitivities to CEvNS and BSM interaction are also discussed., Comment: 12 pages, 7 figures, 1 table

The Fermilab Proton-Improvement-Plan-II (PIP-II) is being implemented in order to support the precision neutrino oscillation measurements at the Deep Underground Neutrino Experiment, the U.S. flagship neutrino experiment. The PIP-II LINAC is presently under construction and is expected to provide 800~MeV protons with 2~mA current. This white paper summarizes the outcome of the first workshop on May 10 through 13, 2023, to exploit this capability for new physics opportunities in the kinematic regime that are unavailable to other facilities, in particular a potential beam dump facility implemented at the end of the LINAC. Various new physics opportunities have been discussed in a wide range of kinematic regime, from eV scale to keV and MeV. We also emphasize that the timely establishment of the beam dump facility at Fermilab is essential to exploit these new physics opportunities.

The formation of giant planets has traditionally been divided into two pathways: core accretion and gravitational instability. However, in recent years, gravitational instability has become less favored, primarily due to the scarcity of observations of fragmented protoplanetary disks around young stars and low occurrence rate of massive planets on very wide orbits. In this study, we present a SPHERE/IRDIS polarized light observation of the young outbursting object V960 Mon. The image reveals a vast structure of intricately shaped scattered light with several spiral arms. This finding motivated a re-analysis of archival ALMA 1.3 mm data acquired just two years after the onset of the outburst of V960 Mon. In these data, we discover several clumps of continuum emission aligned along a spiral arm that coincides with the scattered light structure. We interpret the localized emission as fragments formed from a spiral arm under gravitational collapse. Estimating the mass of solids within these clumps to be of several Earth masses, we suggest this observation to be the first evidence of gravitational instability occurring on planetary scales. This study discusses the significance of this finding for planet formation and its potential connection with the outbursting state of V960 Mon., Comment: Published in ApJL. 11 pages, 4 figures. Images available as fits files at https://github.com/yemsnucleus/V960_Mon_ApJL

We present results from a 3.25 kg-day target exposure of two silicon charge-coupled devices (CCDs), each with 24 megapixels and skipper readout, deployed in the DAMIC setup at SNOLAB. With a reduction in pixel readout noise of a factor of 10 relative to the previous detector, we investigate the excess population of low-energy events in the CCD bulk previously observed above expected backgrounds. We address the dominant systematic uncertainty of the previous analysis through a depth fiducialization designed to reject surface backgrounds on the CCDs. The measured bulk ionization spectrum confirms the presence of an excess population of low-energy events in the CCD target with characteristic rate of ${\sim}7$ events per kg-day and electron-equivalent energies of ${\sim}80~$eV, whose origin remains unknown., Comment: 8 pages, 4 figures

We present ALMA multiwavelength observations of the protoplanetary disk around the nearby (d$\sim$100 pc) young solar analog MP Mus (PDS 66). These observations at 0.89 mm, 1.3 mm, and 2.2 mm have angular resolutions of $\sim$ 1", 0.05", and 0.25", respectively, and probe the dust and gas in the system with unprecedented detail and sensitivity. The disk appears smooth down to the 4 au resolution of the 1.3 mm observations, in contrast with most disks observed at comparable spatial scales. The dust disk has a radius of 60$\pm$5 au, a dust mass of $0.14_{-0.06}^{+0.11} M_{\rm Jup}$, and a mm spectral index $<2$ in the inner 30 au, suggesting optically thick emission from grains with high albedo in this region. Several molecular gas lines are also detected extending up to 130$\pm$15 au, similar to small grains traced by scattered light observations. Comparing the fluxes of different CO isotopologues with previous models yields a gas mass of $0.1-1 M_{\rm Jup}$, implying a gas to dust ratio of 1-10. We also measure a dynamical stellar mass of $M_{\rm dyn}$=1.30$\pm$0.08 $M_\odot$ and derive an age of 7-10 Myr for the system. The survival of large grains in an evolved disk without gaps/rings is surprising, and it is possible that existing substructures remain undetected due to optically thick emission at 1.3 mm. Alternatively, small structures may still remain unresolved with the current observations. Based on simple scaling relations for gap-opening planets and gap widths, this lack of substructures places upper limits to the masses of planets in the disk as low as 2 $M_\oplus$-0.06 $M_{\rm Jup}$ at $r > 40$ au. The lack of mm emission at radii $r > 60$ au also suggests that the gap in scattered light between 30-80 au is likely not a gap in the disk density, but a shadow cast by a puffed-up inner disk., Comment: 17 pages + 3 appendices. Accepted for publication in Astronomy & Astrophysics

We present a new instrument composed of a large number of sub-electron noise Skipper-CCDs operated with a two stage analog multiplexed readout scheme suitable for scaling to thousands of channels. New, thick, $1.35$ Mpix sensors, from a new foundry, are glued into a Multi-Chip Module (MCM) printed circuit board on a ceramic substrate which has 16 sensors each. The instrument, that can hold up-to 16 MCMs, a total of 256 Skipper-CCD sensors (called a Super-Module with $\approx 130$ grams of active mass and $346$ Mpix), is part of the R$\&$D effort of the OSCURA experiment which will have $\approx 94$ super-modules. Experimental results with $10$ MCMs and $160$ Skipper-CCDs sensors are presented in this paper. This is already the largest ever build instrument with single electron sensitivity CCDs using nondestructive readout, both, in terms of active mass and number of channels., Comment: Corrected minor typos

This work briefly discusses the potential applications of the Skipper-CCD technology in astronomy and reviews its current use in dark matter and neutrino experiments. An overview of the ongoing efforts to build multi-kilogram experiments with these sensors is given, in the context of the Oscura experiment. First results from the characterization of Oscura sensors from the first 200 mm wafer-fabrication run with a new vendor are presented. The overall yield of the electron counting capability of these sensors is 71%. A noise of 0.087 e$^-$ RMS, with 1225 samples/pix, and a dark current of (0.031$\pm$0.013) e$^-$/pix/day at 140 K were measured.

Planets have been detected in circumbinary orbits in several different systems, despite the additional challenges faced during their formation in such an environment. We investigate the possibility of planetary formation in the spectroscopic binary CS Cha by analyzing its circumbinary disk. The system was studied with high angular resolution ALMA observations at 0.87mm. Visibilities modeling and Keplerian fitting are used to constrain the physical properties of CS Cha, and the observations were compared to hydrodynamic simulations. Our observations are able to resolve the disk cavity in the dust continuum emission and the 12CO J:3-2 transition. We find the dust continuum disk to be azimuthally axisymmetric (less than 9% of intensity variation along the ring) and of low eccentricity (of 0.039 at the peak brightness of the ring). Under certain conditions, low eccentricities can be achieved in simulated disks without the need of a planet, however, the combination of low eccentricity and axisymmetry is consistent with the presence of a Saturn-like planet orbiting near the edge of the cavity., Comment: 18 pages, 13 figures, accepted in A&A. Watch a 3min summary by the first author in https://youtu.be/6j5ROSj2N-U

X-ray- and extreme-ultraviolet- (XEUV-) driven photoevaporative winds acting on protoplanetary disks around young T-Tauri stars may strongly impact disk evolution, affecting both gas and dust distributions. We compute dust densities for the wind regions of XEUV-irradiated transition disks with gap sizes of 20 and 30 AU, and determine whether they can be observed at wavelengths $0.7 \lesssim \lambda_\mathrm{obs} [\mu\mathrm{m}] \lesssim 1.8$ in scattered and polarised light with current instrumentation. For an XEUV-driven outflow around a $M_* = 0.7 \mathrm{M}_\odot$ T-Tauri star with $L_X = 2 \cdot 10^{30} \mathrm{erg/s}$, we find dust mass-loss rates $\dot{M}_\mathrm{dust} \lesssim 2.0 \cdot 10^{-3} \dot{M}_\mathrm{gas}$, and if we invoke vertical settling, the outflow is quite collimated. The synthesised images exhibit a distinct chimney-like structure. The relative intensity of these chimneys is low, but under optimal conditions, their detection may still be feasible with current instrumentation such as JWST NIRCam and SPHERE IRDIS., Comment: Accepted for publication in A&A. 20+10 pages, 17+12 figures (References updated, minor adjustments.)

Stellar binaries represent a substantial fraction of stellar systems, especially among young stellar objects. Accordingly, binaries play an important role in setting the architecture of a large number of protoplanetary discs. Binaries in coplanar and polar orientations with respect to the circumbinary disc are stable configurations and could induce non-axisymmetric structures in the dust and gas distributions. In this work, we suggest that the structures shown in the central region of the protoplanetary disc HD 169142 are produced by the presence of an inner stellar binary and a circumbinary (P-type) planet. We find that a companion with a mass-ratio of 0.1, semi-major axis of 9.9 au, eccentricity of 0.2, and inclination of 90{\deg}, together with a 2 Jupiter Mass coplanar planet on a circular orbit at 45 au reproduce the structures at the innermost ring observed at 1.3 mm and the shape of spiral features in scattered light observations. The model predicts changes in the disc's dust structure, and star's astrometric parameters, which would allow testing its veracity by monitoring this system over the next 20 years., Comment: 11 pages, 7 figures, accepted for publication in MNRAS

X-ray- and EUV- (XEUV-) driven photoevaporative winds acting on protoplanetary disks around young T-Tauri stars may crucially impact disk evolution, affecting both gas and dust distributions. We constrain the dust densities in a typical XEUV-driven outflow, and determine whether these winds can be observed at $\mu\mathrm{m}$-wavelengths in scattered and polarised light. For an XEUV-driven outflow around a $M_* = 0.7\,\mathrm{M}_\odot$ T-Tauri star with $L_X = 2 \cdot 10^{30}\,\mathrm{erg/s}$, we find a dust mass-loss rate $\dot{M}_\mathrm{dust} \lesssim 4.1 \cdot 10^{-11}\,\mathrm{M_\odot / yr}$ for an optimistic estimate of dust densities in the wind (compared to $\dot{M}_\mathrm{gas} \approx 3.7 \cdot 10^{-8}\,\mathrm{M_\odot / yr}$). The synthesised scattered-light images suggest a distinct chimney structure emerging at intensities $I/I_{\max} < 10^{-4.5}$ ($10^{-3.5}$) at $\lambda_\mathrm{obs} = 1.6$ ($0.4$) $\mu\mathrm{m}$, while the features in the polarised-light images are even fainter. Observations synthesised from our model do not exhibit clear features for SPHERE IRDIS, but show a faint wind signature for JWST NIRCam under optimal conditions. In conclusion, unambiguous detections of photoevaporative XEUV winds launched from primordial disks are at least challenging with current instrumentation; this provides a possible explanation as to why disk winds are not routinely detected in scattered or polarised light., Comment: Accepted for publication in A&A. 15 pages, 11 figures. (Affiliations updated, one reference corrected.)

Understanding how giant planets form requires observational input from directly imaged protoplanets. We used VLT/NACO and VLT/SPHERE to search for companions in the transition disc of 2MASS J19005804-3645048 (hereafter CrA-9), an accreting M0.75 dwarf with an estimated age of 1-2 Myr. We found a faint point source at $\sim$0.7'' separation from CrA-9 ($\sim$108 au projected separation). Our 3-epoch astrometry rejects a fixed background star with a $5\sigma$ significance. The near-IR absolute magnitudes of the object point towards a planetary-mass companion. However, our analysis of the 1.0-3.8$\mu$m spectrum extracted for the companion suggests it is a young M5.5 dwarf, based on both the 1.13-$\mu$m Na index and comparison with templates of the Montreal Spectral Library. The observed spectrum is best reproduced with high effective temperature ($3057^{+119}_{-36}$K) BT-DUSTY and BT-SETTL models, but the corresponding photometric radius required to match the measured flux is only $0.60^{+0.01}_{-0.04}$ Jovian radius. We discuss possible explanations to reconcile our measurements, including an M-dwarf companion obscured by an edge-on circum-secondary disc or the shock-heated part of the photosphere of an accreting protoplanet. Follow-up observations covering a larger wavelength range and/or at finer spectral resolution are required to discriminate these two scenarios., Comment: 24 pages, 14 figures, 4 tables, to be published in MNRAS

Recent observations of resolved cold debris disks at tens of au have revealed that gaps could be a common feature in these Kuiper belt analogues. Such gaps could be evidence for the presence of planets within the gaps or closer-in near the edges of the disk. We present SPHERE observations of HD 92945 and HD 107146, two systems with detected gaps. We constrained the mass of possible companions responsible for the gap to 1-2 M Jup for planets located inside the gap and to less than 5 M Jup for separations down to 20 au from the host star. These limits allow us to exclude some of the possible configurations of the planetary systems proposed to explain the shape of the disks around these two stars. In order to put tighter limits on the mass at very short separations from the star, where direct imaging data are less effective, we also combined our data with astrometric measurements from Hipparcos and Gaia and radial velocity measurements. We were able to limit the separation and the mass of the companion potentially responsible for the proper motion anomaly of HD 107146 to values of 2-7 au and 2-5 M Jup , respectively., Comment: 17 pages, 14 Figures, accepted for publication on MNRAS

Radial substructure in the form of rings and gaps has been shown to be ubiquitous among protoplanetary discs. This could be the case in exoKuiper belts as well, and evidence for this is emerging. In this paper we present ALMA observations of the debris/planetesimal disc surrounding HD 206893, a system that also hosts two massive companions at 2 and 11 au. Our observations reveal a disc extending from 30 to 180 au, split by a 27 au wide gap centred at 74 au, and no dust surrounding the reddened brown dwarf (BD) at 11 au. The gap width suggests the presence of a 0.9 M$_\mathrm{Jup}$ planet at 74 au, which would be the third companion in this system. Using previous astrometry of the BD, combined with our derived disc orientation as a prior, we were able to better constrain its orbit finding it is likely eccentric ($0.14^{+0.05}_{-0.04}$). For the innermost companion, we used RV, proper motion anomaly and stability considerations to show its mass and semi-major axis are likely in the range 4-100 M$_\mathrm{Jup}$ and 1.4-4.5 au. These three companions will interact on secular timescales and perturb the orbits of planetesimals, stirring the disc and potentially truncating it to its current extent via secular resonances. Finally, the presence of a gap in this system adds to the growing evidence that gaps could be common in wide exoKuiper belts. Out of 6 wide debris discs observed with ALMA with enough resolution, 4-5 show radial substructure in the form of gaps.

If one analyses the quantum creation of the universe, it turns out that the most natural way in which the universes can be created is in pairs of universes whose time flow is reversely related. It means that the matter that propagates in one of the universes can be seen, from the point of view of the other universe, as antimatter, and viceversa. They thus form a universe-antiuniverse pair. From a global point of view, i.e. from the point of view of the whole multiverse ensemble, the creation of universes in universe-antiuniverse pairs restores the matter-antimatter asymmetry observed in each individual universe and it might provide us with distinguishable imprints of the whole multiverse proposal., Comment: 7 pages, 3 figures, prepared for the proceedings of the POTOR-6 Conference of the Polish Society on Relativity, held in Szczecin (Poland) from 23-26th of Sept. 2019

The mechanisms of planet formation are still under debate. We know little about how planets form, even if more than 4000 exoplanets have been detected to date. Recent investigations target the cot of newly born planets: the protoplanetary disk. At the first stages of their life, exoplanets still accrete material from the gas-rich disk in which they are embedded. Transitional disks are indeed disks that show peculiarities, such as gaps, spiral arms, and rings, which can be connected to the presence of substellar companions. To investigate what is responsible for these features, we selected all the known transitional disks in the solar neighborhood (<200 pc) that are visible from the southern hemisphere. We conducted a survey of 11 transitional disks (TDs) with the SPHERE instrument at the VLT. This is the largest Halpha survey that has been conducted so far to look for protoplanets. The observations were performed with the Halpha filter of ZIMPOL in order to target protoplanets that are still in the accretion stage. All the selected targets are very young stars, less than 20 Myr, and show low extinction in the visible. We reduced the ZIMPOL pupil stabilized data by applying the method of the angular spectral differential imaging (ASDI), which combines both techniques. The datacubes are composed of the CntHalpha and the narrow band filter Halpha, which are taken simultaneously to permit the suppression of the speckle pattern. The principal component analysis (PCA) method was employed for the reduction of the data. For each dataset, we derived the 5sigma contrast limit and converted it in upper limits on the accretion luminosity. We do not detect any new accreting substellar companions around the targeted transition disks down to an average contrast of 12 magnitudes at 0.2 arcsec from the central star (continues in the manuscript)., Comment: Accepted for publication in A&A. 10 pages, 16 figures

Compact objects have an intrinsic anisotropy due to the presence of strong magnetic fields that cause considerable modifications on the equations of state (EoS). In this work, we study the impact of this anisotropy in the size and shape of magnetized strange quark stars using an axially symmetric metric in spherical coordinates, the gamma-metric. The results are compared with those obtained with the standard Tolman-Oppenheimer-Volkoff (TOV) equations for the parallel and perpendicular pressures independently. Differences in the results are discussed., Comment: 5 pages, 5 figures, Proceedings of STARS-SMFNS 2019

We still do not understand how planets form, or why extra-solar planetary systems are so different from our own solar system. But the last few years have dramatically changed our view of the discs of gas and dust around young stars. Observations with the Atacama Large Millimeter/submillimeter Array (ALMA) and extreme adaptive-optics systems have revealed that most --- if not all --- discs contain substructure, including rings and gaps, spirals, azimuthal dust concentrations, and shadows cast by misaligned inner discs. These features have been interpreted as signatures of newborn protoplanets, but the exact origin is unknown. Here we report the kinematic detection of a few Jupiter-mass planet located in a gas and dust gap at 130 au in the disc surrounding the young star HD 97048. An embedded planet can explain both the disturbed Keplerian flow of the gas, detected in CO lines, and the gap detected in the dust disc at the same radius. While gaps appear to be a common feature in protoplanetary discs, we present a direct correspondence between a planet and a dust gap, indicating that at least some gaps are the result of planet-disc interactions., Comment: preprint Nature Astronomy, 4 figures, 1 table, 8 suplementary figures

Context: The complex system HD 100453 AB with a ring-like circumprimary disk and two spiral arms, one of which is pointing to the secondary, is a good laboratory to test spiral formation theories. Aims: To quantify the interaction of HD 100453 B with the circumprimary disk. Methods: Using ALMA band 6 dust continuum and CO isotopologue observations we study the HD 100453 AB system with a spatial resolution of 0.09" x 0.17" at 234 GHz. We use SPH simulations and orbital fitting to investigate the tidal influence of the companion on the disk. Results: We resolve the continuum emission around HD 100453 A into a disk between 0.22" and 0.40" with an inclination of 29.5 deg. and a position angle of 151.0 deg., an unresolved inner disk, and excess mm emission cospatial with the northern spiral arm which was previously detected using scattered light observations. We also detect CO emission from 7 au (well within the disk cavity) out to 1.10", i.e., overlapping with HD 100453 B at least in projection. The outer CO disk PA and inclination differ by up to 10 deg. from the values found for the inner CO disk and the dust continuum emission, which we interpret as due to gravitational interaction with HD 100453 B. Both the spatial extent of the CO disk and the detection of mm emission at the same location as the northern spiral arm are in disagreement with the previously proposed near co-planar orbit of HD 100453 B. Conclusions: We conclude that HD 100453 B has an orbit that is significantly misaligned with the circumprimary disk. Because it is unclear whether such an orbit can explain the observed system geometry we highlight an alternative scenario that explains all detected disk features where another, (yet) undetected, low mass close companion within the disk cavity, shepherds a misaligned inner disk whose slowly precessing shadows excite the spiral arms., Comment: Accepted in Astronomy and Astrophysics

The effect of magnetic fields in the Equations of State (EoS) of compact objects is the splitting of the pressure in two components, one parallel and the other perpendicular to the magnetic field. This anisotropy suggests the necessity of using structure equations considering the axial symmetry of the magnetized system. In this work, we consider an axially symmetric metric in spherical coordinates, the $\gamma$-metric, and construct a system of equations to describe the structure of spheroidal compact objects. In addition, we connect the geometrical parameter $\gamma$ linked to the spheroid's radii, with the source of the anisotropy. So, the model relates the shape of the compact object to the physics that determines the properties of the composing matter. To illustrate how our structure equations work, we obtain the mass-radii solutions for magnetized White Dwarfs. Our results show that the main effect of the magnetic field anisotropy in White Dwarfs structure is to cause a deformation of these objects. Since this effect is only relevant at low densities, it does not affect the maximum values of magnetized White Dwarf's masses, which remain under Chandrasekhar limit., Comment: 9 pages, 7 figures, re-written version submitted for publication in Phys. Rev. D

The precise and continuous tracking of millimetric-sized walkers --such as ants-- is quite important in behavioral studies. However, due to technical limitations, most studies concentrate on trajectories within arenas no more than 100 times bigger than the size of the walker or longer trajectories at the expense of either accuracy or continuity. Our work describes a scientific instrument designed to push the boundaries of precise and continuous motion analysis up to 1000 body lengths or more. It consists of a mobile robotic platform that uses Digital Image Processing techniques to track the targets in real time by calculating their spatial position. During the experiments, all the images are stored, and afterwards processed to estimate with higher precision the path traced by the walkers. Some preliminary results achieved using the proposed tracking system are presented.

We present Atacama Large Millimeter/submillimeter Array (ALMA) observations at 0.3 arcsec-resolution of EX Lup, the prototype of the EXor class of outbursting pre-main sequence stars. The circumstellar disk of EX Lup is resolved for the first time in 1.3mm continuum emission and in the $J$=2--1 spectral line of three isotopologues of CO. At the spatial resolution and sensitivity achieved, the compact dust continuum disk shows no indications of clumps, fragments, or asymmetries above 5-sigma level. Radiative transfer modeling constrains the characteristic radius of the dust disk to 23 au and a total dust mass of 1.0$\times$10$^{-4}$ M$_\odot$ (33 M_earth), similar to other EXor sources. The $^{13}$CO and C$^{18}$O line emission trace the disk rotation and are used to constrain the disk geometry, kinematics, and a total gas disk mass of 5.1$\times$10$^{-4}$ M$_\odot$. The $^{12}$CO emission extends out to a radius of 200 au and is asymmetric, with one side deviating from Keplerian rotation. We detect blue-shifted, $^{12}$CO arc-like emission located 0.8 arcsec to the north-west, and spatially disconnected from the disk emission. We interpret this extended structure as the brightened walls of a cavity excavated by an outflow, which are more commonly seen in FUor sources. Such outflows have also been seen in the borderline FU/EXor object V1647 Ori, but not towards EXor objects. Our detection provides evidence that the outflow phenomenon persists into the EXor phase, suggesting that FUor and EXor objects are a continuous population in which outflow activity declines with age, with transitional objects such as EX Lup and V1647 Ori.

During the shutdown of the CERN Large Hadron Collider in 2013-2014, an additional pixel layer was installed between the existing Pixel detector of the ATLAS experiment and a new, smaller radius beam pipe. The motivation for this new pixel layer, the Insertable B-Layer (IBL), was to maintain or improve the robustness and performance of the ATLAS tracking system, given the higher instantaneous and integrated luminosities realised following the shutdown. Because of the extreme radiation and collision rate environment, several new radiation-tolerant sensor and electronic technologies were utilised for this layer. This paper reports on the IBL construction and integration prior to its operation in the ATLAS detector., Comment: 90 pages in total. Author list: ATLAS IBL Collaboration, starting page 2. 69 figures, 20 tables. Published in Journal of Instrumentation. All figures available at: https://atlas.web.cern.ch/Atlas/GROUPS/PHYSICS/PLOTS/PIX-2018-001

We present new data of the protoplanetary disc surrounding the Herbig Ae/Be star HD 169142 obtained in the very broad-band (VBB) with the Zurich imaging polarimeter (ZIMPOL), a sub-system of the Spectro-Polarimetric High-contrast Exoplanet REsearch instrument (SPHERE) at the Very Large Telescope (VLT). Our Polarimetric Differential Imaging (PDI) observations probe the disc as close as 0.03" (3.5au) to the star and are able to trace the disc out to ~1.08" (~126au). We find an inner hole, a bright ring bearing substructures around 0.18" (21au), and an elliptically shaped gap stretching from 0.25" to 0.47" (29-55au). Outside of 0.47", the surface brightness drops off, discontinued only by a narrow annular brightness minimum at ~0.63"-0.74" (74-87au). These observations confirm features found in less-well resolved data as well as reveal yet undetected indications for planet-disc interactions, such as small-scale structures, star-disk offsets, and potentially moving shadows., Comment: Accepted for publication in MNRAS

Understanding the emergence of biodiversity patterns in nature is a central problem in biology. Theoretical models of speciation have addressed this question in the macroecological scale, but little has been investigated in the macroevolutionary context. Knowledge of the evolutionary history allows the study of patterns underlying the processes considered in these models, revealing their signatures and the role of speciation and extinction in shaping macroevolutionary patterns. In this paper we introduce two algorithms to record the evolutionary history of populations in individual-based models of speciation, from which genealogies and phylogenies can be constructed. The first algorithm relies on saving ancestral-descendant relationships, generating a matrix that contains the times to the most recent common ancestor between all pairs of individuals at every generation (the Most Recent Common Ancestor Time matrix, MRCAT). The second algorithm directly records all speciation and extinction events throughout the evolutionary process, generating a matrix with the true phylogeny of species (the Sequential Speciation and Extinction Events, SSEE). We illustrate the use of these algorithms in a spatially explicit individual-based model of speciation. We compare the trees generated via MRCAT and SSEE algorithms with trees inferred by methods that use only genetic distance among extant species, commonly used in empirical studies and applied here to simulated genetic data. Comparisons between tress are performed with metrics describing the overall topology, branch length distribution and imbalance of trees. We observe that both MRCAT and distance-based trees differ from the true phylogeny, with the first being closer to the true tree than the second., Comment: This is a revised version, with a new title and 2 new co-authors. 24 pages, 7 figures

We report measurements of the temperature dependence specific heat, magnetic susceptibility in single crystals of the series of intermetallic compounds Tb$_{1-x}$Y$_x$RhIn$_5$ (nominal concentrations $x= 0.15, 0.30, 0.40, 0.50$ and $0.70$). A mean field approximation to simulate the macroscopic properties along the series has been used. Neutron diffraction data in powdered sample of nominal concentration Tb$_{0.6}$Y$_{0.4}$RhIn$_5$ reveal AFM propagation vector $k=[\frac{1}{2}~0~\frac{1}{2}]$ with the magnetic moments oriented close to the tetragonal \textit{c} axis. We discuss the role of combined effects of crystalline electric field (CEF) perturbations and dilution in the magnetic properties evolution with Y content. In particular, we suggest that changes in the Tb-In first neighbors distances, i.e. the TbIn$_3$ cuboctahedra distortion, are responsible for changes in the Tb crystalline potential and the possible reorientation of Tb magnetic moments for $x>$0.4. This reflects non negligible variations of the $B^{m}_{n}$ crystal field parameters and the energy levels splitting with \textit{x}.

CO observations allow estimations of the gas content of molecular clouds, which trace the reservoir of cold gas fuelling star formation, as well as to determine extinction via H$_2$ column density, N(H$_2$). Here, we studied millimetric and optical properties at 26 supernovae (SNe) locations of different types in a sample of 23 nearby galaxies by combining molecular $^{12}$C$^{16}$O (J = 1 $\rightarrow$ 0) resolved maps from the EDGE survey and optical Integral Field Spectroscopy from the CALIFA survey. We found an even clearer separation between type II and type Ibc SNe in terms of molecular gas than what we found in the optical using H$\alpha$ emission as a proxy for current SF rate, which reinforces the fact that SNe Ibc are more associated with SF-environments. While A$_V$ at SN locations is similar for SNe II and SNe Ibc, and higher compared to SNe Ia, N(H$_2$) is significantly higher for SNe Ibc than for SNe II and SNe Ia. When compared to alternative extinction estimations directly from SN photometry and spectroscopy, we find that our SNe Ibc have also redder color excess but showed standard Na I D absorption pseudo-equivalent widths ($\sim$1 \AA). In some cases we find no extinction when estimated from the environment, but high amounts of extinction when measured from SN observations, which suggests that circumstellar material or dust sublimation may be playing a role. This work serves as a benchmark for future studies combining last generation millimeter and optical IFS instruments to reveal the local environmental properties of extragalactic SNe., Comment: MNRAS accepted, 17 pages, 8 Figures, 4 Tables

We present Atacama Large Millimeter/sub-millimeter Array (ALMA) Cycle-2 observations of the HBC 494 molecular outflow and envelope. HBC 494 is an FU Ori-like object embedded in the Orion A cloud and is associated with the reflection nebulae Re50 and Re50N. We use $^{12}$CO, $^{13}$CO and C$^{18}$O spectral line data to independently describe the outflow and envelope structures associated with HBC 494. The moment-1 map of the $^{12}$CO emission shows the widest outflow cavities in a Class I object known to date (opening angle $\sim$ 150$^{^{\circ}}$). The morphology of the wide outflow is likely to be due to the interaction between winds originating in the inner disc and the surrounding envelope. The low-velocity blue- and red-shifted $^{13}$CO and C$^{18}$O emission trace the rotation and infall motion of the circumstellar envelope. Using molecular line data and adopting standard methods for correcting optical depth effects, we estimate its kinematic properties, including an outflow mass on the order of 10$^{-1}$ M$_{\odot}$. Considering the large estimated outflow mass for HBC 494, our results support recent theoretical work suggesting that wind-driven processes might dominate the evolution of protoplanetary discs via energetic outflows., Comment: 14 pages, 12 Figures

A geometric method for obtaining an infinite family of Cayley digraphs of constant density on finite Abelian groups is presented. The method works for any given degree and it is based on consecutive dilates of a minimum distance diagram associated with a given initial Cayley digraph. The method is used to obtain infinite families of dense or asymptotically dense Cayley digraphs. In particular, for degree $d=3$, an infinite family of maximum known density is proposed.

Context: Gaps, cavities and rings in circumstellar disks are signposts of disk evolution and planet-disk interactions. We follow the recent suggestion that Herbig Ae/Be disks with a flared disk harbour a cavity, and investigate the disk around HD~97048. Aims: We aim to resolve the 34$\pm$ 4 au central cavity predicted by Maaskant et al. (2013) and to investigate the structure of the disk. Methods: We image the disk around HD~97048 using ALMA at 0.85~mm and 2.94~mm, and ATCA (multiple frequencies) observations. Our observations also include the 12CO J=1-0, 12CO J=3-2 and HCO+ J=4-3 emission lines. Results: A central cavity in the disk around HD~97048 is resolved with a 40-46 au radius. Additional radial structure present in the surface brightness profile can be accounted for either by an opacity gap at ~90 au or by an extra emitting ring at ~150 au. The continuum emission tracing the dust in the disk is detected out to 355 au. The 12CO J=3-2 disk is detected 2.4 times farther out. The 12CO emission can be traced down to $\approx$ 10 au scales. Non-Keplerian kinematics are detected inside the cavity via the HCO+ J=4-3 velocity map. The mm spectral index measured from ATCA observations suggests that grain growth has occurred in the HD~97048 disk. Finally, we resolve a highly inclined disk out to 150 au around the nearby 0.5~$M_{\odot}$ binary ISO-ChaI 126. Conclusions: The data presented here reveal a cavity in the disk of HD 97048, and prominent radial structure in the surface brightness. The cavity size varies for different continuum frequencies and gas tracers. The gas inside the cavity follows non-Keplerian kinematics seen in HCO+ emission. The variable cavity size along with the kinematical signature suggests the presence of a substellar companion or massive planet inside the cavity., Comment: 18 pages, 16 figures. Accepted to Astronomy & Astrophysics September 3rd 2016

An increasing number of observations have shown that gaseous debris discs are not an exception. However, until now we only knew of cases around A stars. Here we present the first detection of 12CO (2-1) disc emission around an F star, HD 181327, obtained with ALMA observations at 1.3 mm. The continuum and CO emission are resolved into an axisymmetric disc with ring-like morphology. Using a Markov chain Monte Carlo method coupled with radiative transfer calculations we study the dust and CO mass distribution. We find the dust is distributed in a ring with a radius of 86.0 +- 0.4 AU and a radial width of 23.2 +- 1.0 AU. At this frequency the ring radius is smaller than in the optical, revealing grain size segregation expected due to radiation pressure. We also report on the detection of low level continuum emission beyond the main ring out to ~200 AU. We model the CO emission in the non-LTE regime and we find that the CO is co-located with the dust, with a total CO gas mass ranging between 1.2x10^-6 Mearth and 2.9x10^-6 Mearth, depending on the gas kinetic temperature and collisional partners densities. The CO densities and location suggest a secondary origin, i.e. released from icy planetesimals in the ring. We derive a CO+CO2 cometary composition that is consistent with Solar system comets. Due to the low gas densities it is unlikely that the gas is shaping the dust distribution., Comment: Accepted for publication in MNRAS

We examine a new multiverse scenario in which the component universes interact. We focus our attention to the process of "true" vacuum nucleation in the false vacuum within one single element of the multiverse. It is shown that the interactions lead to a collective behaviour that might lead, under specific conditions, to a pre-inflationary phase and ensued distinguishable imprints in the comic microwave background radiation., Comment: 9 pages, 5 figures

The formation of planetesimals requires that primordial dust grains grow from micron- to km-sized bodies. Dust traps caused by gas pressure maxima have been proposed as regions where grains can concentrate and grow fast enough to form planetesimals, before radially migrating onto the star. We report new VLA Ka & Ku observations of the protoplanetary disk around the Herbig Ae/Be star MWC 758. The Ka image shows a compact emission region in the outer disk indicating a strong concentration of big dust grains. Tracing smaller grains, archival ALMA data in band 7 continuum shows extended disk emission with an intensity maximum to the north-west of the central star, which matches the VLA clump position. The compactness of the Ka emission is expected in the context of dust trapping, as big grains are trapped more easily than smaller grains in gas pressure maxima. We develop a non-axisymmetric parametric model inspired by a steady state vortex solution with parameters adequately selected to reproduce the observations, including the spectral energy distribution. Finally, we compare the radio continuum with SPHERE scattered light data. The ALMA continuum spatially coincides with a spiral-like feature seen in scattered light, while the VLA clump is offset from the scattered light maximum. Moreover, the ALMA map shows a decrement that matches a region devoid of scattered polarised emission. Continuum observations at a different wavelength are necessary to conclude if the VLA-ALMA difference is an opacity or a real dust segregation., Comment: Accepted for publication in ApJ

Context. Z\,CMa is a binary composed of an embedded Herbig Be and an FU Ori class star separated by $\sim100$ au. Observational evidence indicate a complex environment in which each star has a circumstellar disk and drives a jet, and the whole system is embedded in a large dusty envelope. Aims. We aim to probe the circumbinary environment of Z\,CMa in the inner 400 au in scattered light. Methods. We use high contrast imaging polarimetry with VLT/NaCo at $H$ and $K_s$ bands. Results. The central binary is resolved in both bands. The polarized images show three bright and complex structures: a common dust envelope, a sharp extended feature previously reported in direct light, and an intriguing bright clump located $0\farcs3$ south of the binary, which appears spatially connected to the sharp extended feature. Conclusions.We detect orbital motion when compared to previous observations, and report a new outburst driven by the Herbig star. Our observations reveal the complex inner environment of Z\,CMa with unprecedented detail and contrast., Comment: Accepted for publication in A&A Letters

Abelian Cayley digraphs can be constructed by using a generalization to $Z^n$ of the concept of congruence in $Z$. Here we use this approach to present a family of such digraphs, which, for every fixed value of the degree, have asymptotically large number of vertices as the diameter increases. Up to now, the best known asymptotically dense results were all non-constructive.

The magnetic and electronic properties of Eu2Ru2O7 are discussed in terms of the local ruthenium and europium coordinations, electronic band structure calculations and molecular orbital energy levels. A preliminary electronic structure was calculated within the LDA and LSDA+U approximations. The molecular orbital energy level diagrams have been used to interpret the Eu-Ru ligand spectrum and the ensuing magnetic properties. The orbital hybridizations and bonds are discussed., Comment: 4 pages

The disk around HD 142527 attracts a lot of attention, amongst others because of its resolved (sub) mm dust continuum that is concentrated into a horseshoe-shape towards the north of the star. In this manuscript we present spatially resolved ALMA detections of the HCN J=4-3 and CS J=7-6 emission lines. These lines give us a view deeper into the disk compared to the (optically thicker) CO isotopes. This is the first detection of CS J=7-6 coming from a protoplanetary disk. Both emission lines are azimuthally asymmetric and are suppressed under the horseshoe-shaped continuum emission peak. A possible mechanism to explain the decrease under the horseshoe-shaped continuum is the increased opacity coming from the higher dust concentration at the continuum peak. Lower {\gr dust and/or gas} temperatures and an optically thick radio-continuum reduce line emission by freeze-out and shielding of emission from the far side of the disk., Comment: 5 pages, 5 figures. Accepted for publication in ApJ Letters

We carried out a 12CO(3-2) survey of 52 southern stars with a wide range of IR excesses (LIR/L*) using the single dish telescopes APEX and ASTE. The main aims were (1) to characterize the evolution of molecular gas in circumstellar disks using LIR/L* values as a proxy of disk dust evolution, and (2) to identify new gas-rich disk systems suitable for detailed study with ALMA. About 60% of the sample (31 systems) have LIR/L* > 0.01 typical of T-Tauri or Herbig AeBe stars, and the rest (21 systems) have LIR/L* < 0.01 typical of debris disks. We detect CO(3-2) emission from 20 systems, and 18 (90%) of these have LIR/L* > 0.01. However, the spectra of only four of the newly detected systems appear free of contamination from background or foreground emission from molecular clouds. These include the early-type stars HD 104237 (A4/5V, 116 pc) and HD 98922 (A2 III, 507 pc, as determined in this work), where our observations reveal the presence of CO-rich circumstellar disks for the first time. Of the other detected sources, many could harbor gaseous circumstellar disks, but our data are inconclusive. For these two newly discovered gas-rich disks, we present radiative transfer models that simultaneously reproduce their spectral energy distributions and the 12CO(3-2) line profiles. For both of these systems, the data are fit well by geometrically flat disks, placing them in the small class of non-flaring disks with significant molecular gas reservoirs., Comment: 73 pages, 23 figures

The excitation energies of states belonging to the ground state bands of heavy even-even nuclei are analysed using recurrence relations. Excellent agreement with experimental data at the 10 keV level is obtained by taking into account strong correlations which emerge in the analysis. This implies that the excitation energies can be written as a polynomial of maximum degree four in the angular momentum., Comment: 4 pages, 1 figure, 1 table, 9 references

Inter-universal entanglement may even exist in a multiverse in which there is no common space-time among the universes. In particular, the entanglement between the expanding and contracting branches of the universe might have observable consequences in the dynamical and thermodynamical properties of one single branch, making therefore testable the whole multiverse proposal, at least in principle., Comment: 4 pages. Prepared for the proceedings of the Multiverse and Fundamental Cosmology Meeting (Multicosmofun'12)

The boundary conditions to be imposed on the quantum state of the whole multiverse could be such that the universes would be created in entangled pairs. Then, inter-universal entanglement would provide us with a vacuum energy for each single universe that might be fitted with observational data, making testable not only the multiverse proposal but also the boundary conditions of the multiverse. Furthermore, the second law of the entanglement thermodynamics would enhance the expansion of the single universes., Comment: 3 pages, no figure. Prepared for the proceedings of the "Thirteenth Marcel Grossmann Meeting"

The third quantization formalism of quantum cosmology adds simplicity and conceptual insight into the quantum description of the multiverse. Within such a formalism, the existence of squeezed and entangled states raises the question of whether the complementary principle of quantum mechanics has to be extended to the quantum description of the whole space-time manifold. If so, the 'particle' description entails the consideration of a multiverse scenario and the 'wave' description induces us to consider as well correlations and interactions among the universes of the multiverse., Comment: 4 pages. Proceedings of the International Conference on Mathematical Modeling in Physical Sciences, September 3-7, 2012, Budapest, Hungary